Making first intricate mesh on my own after tutorials, need some pointers
One element of the eventual solution might be to model each button group as its own mesh and then join the different button groups into a complete object at the end of the process (and keep a copy of the separated versions in a second .blend file in case you need to make some tweaks).

Loop cuts are not the ONLY tool available to you.  Subdivision (of faces or edges) can be of considerable utility as well.  However, it can lead to inconvenient temporary situations if you do things in the "wrong" order.  Expect to do things inefficiently for many many tries until you get a feel for the "right" way to do things.  It is just part of the learning process.

Yes: non-quads can be inconvenient when dealing with subsurfs.  Their problems are mostly concealed when they happen to be coplanar will all their neighbors, so you can exploit that.

Another thing you can exploit is that loop cuts try to be straight across, but you can relocate some of the edges of the loops in another part of the mesh to deal with different button dimensions or spacing.